Hydraulic controller



Feb. 3, 1970 w. A. RAY 3,492,921

HYDRAULIC CONTROLLER Filed Dec. 21. 1967 a Sheets-Sheet 1 INVENTORW/d/AM ,4. 16/4 V A from 6V 4 Feb. 3, 1970 w. A. R Y 3,492,921

HYDRAULIC CONTROLLER Filed Dec. 21. 1967 6 Sheets-Sheet 2 INVENTOR W/a/AA 5W A TTOE/V'y Feb. 3, 1970 w. A. RAY

HYDRAULIC CONTROLLER 6 Sheets-Sheet 3 Filed Dec. 21. 1967 ATTOK/VEV Feb.3, 1970 I w. A. RAY 3, ,9

HYDRAULIC CONTROLLER Filed Dec. 21, 1967 6 Sheets-Sheet 4 INVENTOR EZ'Q6' W/A/AMA 64y ATTOZ/Vy 6 Sheets-Sheet 5 Filed Dec. 21, 1967 INVENTOR lV//AM A. my

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HYDRAULIC CONTROLLER 6 Sheets-Sheet 6 Filed Dec. 21, 1967 T M NA 6 EB 0MA W M A m 1 4 W United States Patent O 3,492,921 HYDRAULIC CONTROLLERWilliam A. Ray, North Hollywood, Calif., assignor to InternationalTelephone and Telegraph Corporation, New York, N.Y., a corporation ofMaryland Filed Dec. 21, 1967, Ser. No. 692,392 Int. Cl. F151) 13/06,13/16 US. Cl. 9151 8 Claims ABSTRACT OF THE DISCLOSURE The inventionincludes an improvement on hydraulic apparatus which controls a largepressure by the use of a small change in pressure in a hydraulicamplifier, The small change in pressure is provided by varying theamount of hydraulic fluid which is permitted to escape from a bleednozzle by the use of a vane movable toward and away from the nozzleorifice. The improvement comprises a diaphragm responsive to thepressure of hydraulic fluid in the nozzle to move the vane toward thenozzle orifice. This arrangement provides positive feedback whichconsiderably increases the speed of response of the apparatus.

BACKGROUND OF THE INVENTION This invention relates to hydraulic controlsand more particularly to a hydraulic feedback system to increase thespeed of response of a hydraulic amplifier.

In the past, hydraulic amplifiers have been used very successfully incontrolling extremely large loads with very small input pressurechanges. However, such devices are often required to operate at speedsgreater than are, at present, possible.

SUMMARY OF THE INVENTION In accordance with the device of the presentinvention, the above-described and other disadvantages of the part areovercome by providing positive feedback for a hydraulic amplifier.

In the past, conventional hydraulic amplifiers such as that disclosed inFIG. of W. A. Ray, US. Patent No. 3,087,471 employ a vane which providesa variable restriction at the orifice of a nozzle to control thehydraulic pressure inside the nozzle and to a cylinder having a pistontherein. It is thus possible to control an extremely large force bycontrolling the fluid which is bled through the nozzle orifice. Inaccordance with the device of the present invention, means responsive tothe increase in pressure inside the nozzle is employed to move the vanein a direction to close off the nozzle even more. Positive feedback isthereby provided. Thus, the device of the present invention can, as inthe prior art, control a very large force with a small one, and yetprovide for a rapid speed of response due to the said positive feedback.

The above-described and other advantages of the present invention willbe better understood from the following descriptiOn when considered inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, which are to beregarded as merely illustrative:

FIG. 1 is a vertical sectional view through a control device of thepresent invention;

FIG. 2 is a vertical sectional view similar to FIG. 1 showing a portionof an orifice opening control device;

FIG. 3 is a top plan view of the control devices shown in FIGS. 1 and 2;

FIG. 4 is a side elevational view of the control device as shown in FIG.3;

3,492,921 Patented Feb. 3, 1970 DESCRIPTION OF THE PREFERRED EMBODIMENTSIn the drawings in FIG. 1, one embodiment of the control device of thepresent invention is indicated at 20. Control device 20 has a housing 21for an electric motor 22 which operates pumps 23 and 24 identical tothose shown in the aforementioned patent. The outputs of pumps 23 and 24provide inputs at 25 and 26 respectively to opposite ends of thecylinder 27. Thus, a difference in pressure at opposite ends of cylinder27 will cause a piston 28 therein to move in one of two directions.Piston 28 has a rod 29 afiixed thereto which may adjust the opening at avalve or perform any other mechanical function. Alternatively, one ofthe cylinder inputs at 25 or 26 may be omitted and piston 28 may bespring biased, if desired. Such an arrangement is shown in FIG. 5 ofU.S. Patent No. 3,087,471.

The pressure on opposite sides of piston 28 is controlled by hydraulicamplifiers 30 and 31 identical to that shown in the said patent, Theoutputs of hydraulic amplifiers 30 and 31 are bled through nozzles 32and 33 respectively. A vane 34 pivoted at 35 controls the amount ofhydraulic fluid which may be bled from nozzles 32 and 33.

Positive feedback is provided by connections 36 and 37 to chambers 38and 39 respectively. Thus, an increase in pressure in nozzle 32 willtend to move vane 34 to close nozzle 32 through a diaphragm 40.Similarly, an increase in pressure inside nozzle 33 will tend to closenozzle 33 by a diaphragm 41.

A servo balance control 42 is connected from vane 34 to piston rod 29.Control 42 may be entirely conventional, if desired.

In the operation of the invention shown in FIG. 1, piston 28 willnormally assume a position in cylinder 27 depending upon how van 34 ismoved by control 42. When piston 28 is in the proper position, vane 34will be located substantially midway between nozzles 32 and 33. Shouldcontrol 42 tend to close nozzle 32 and open nozzle 33, hydraulicamplifier 30 will cause an increase in pressure in connection 25 andtherefore move piston 28 upwardly. This condition will occur until vane34 is again placed substantially midway between nozzles 32 and 33.During this transient response, the increase in pressure inside nozzle32 created by vane 34 moving toward the same will be transmitted throughconnection 36 to tend to close nozzle 32. A degree of positive feedbackwill increase the speed of response of the device 20. Movement of piston28 downwardly will take place in the same manner. The operation ofhydraulic amplifiers 3G and 31 are identical to that disclosed in thesaid patent. The said patent should therefore be referred to for adetailed description of the ope ation thereof. A cavity on chamber 43 isprovided at the bottom of housing 21. Opening from the chamber 44 inwhich nozzles 32 and 33 are located is then provided in the conventionalway. The same is true of the chambers in which amplifier springs 45 and46 are located.

A more detailed showing of the device 20 is illustrated in FIG. 2.Connections 36 and 37 have been omitted for clarity. Note will be takenthat vane 34 is supported on flexure strips 94 shown in FIGS. 8 and 9and sealed from upper chamber by a spring metal bellows 47. An arm 48 isfixed to vane 34 at the top of bellows 47. A cylindrical balance weight49- is threaded through arm 48. Arm 48 is moved through anelectromagnetic device 50 which may be conventional. A ferromagneticcore is provided at 51 which changes the position of a coil 52 fixed toarm 48 depending upon the amount of current which is supplied to coil52.

As shown in FIGS. 3 and 4, piston rod 29 lifts an arm 53 pivoted on ashaft 54 when piston rod 29 rises. Arm 53 has a slot 55 through which apin 56 is located. Pin 56 has flanges 57 on each side of arm 53 to holdpin 56 in slot 55. An arm 58 fixed to another arm 59 at 60 is pivotedfrom a shaft 61. As arm 59 moves upwardly the upper end 62 of a spring63 is pulled upwardly by a wire 64 hooked to spring end 62 and fixed toarm 59 by a screw 65. The lower end of spring 63 is fixed to arm 48.Spring 63 and the other linkages between piston rod 29 and arm 49 thusprovide a feedback from piston rod 29 to vane 34 through arm 48. Thisfeedback may be conventional, if desired.

An alternative arrangement for controlling the position of vane 66 isshown at 67 in FIG. 5. This arrangement will be used when piston 28 isspring biased thus, only one nozzle 68 is employed. As before,arrangement 67 includes an arm 69 from which vane 66 is suspended.Flexure strips, not shown, support arm 69. Bellows 70 seals hydraulicfluid within chamber 47'. As before, a weight 71 is provided at one endof arm 69 and a coil 72 is provided at the other end thereof. Coil 72 islocated around a ferromagnetic core 73. The same linkage may be employedfor mechanical feedback from piston rod 29 to arm 69 as shown in FIGURES3 and 4.

Still another arrangement similar to but somewhat different thanarrangement 67 as indicated at 74 in FIG. 6. In this case, all of thestructure shown is non-magnetic except for two vertical permanentmagnets, now shown. One magnet may be located in a plane perpendicularto a supporting shaft 75 at one end thereof, and the other located atthe other end thereof. Each permanent magnet may be simply a rectangularbar magnet polarized in the vertical direction so that the poles of bothmagnets will be the same at their upper ends and the same at their lowerends. An armature is rotatively suspended under shaft 75 which is fixedto non-magnetic side support plates, not shown. Energization of coils 76and 77 will cause armature 78 to rotate about the center of shaft 75.Stops 80 and 81 are provided for armature 78, stops 80 and 81 beingfixed to housing 79 by means of screws 82 and 83 respectively.

Similar to the embodiment of FIG. 5, a vane 84 for nozzle 85 is fixed toarm 78.

Still another embodiment of the invention is shown in FIG. 7 whichincludes coils 86 and 87 around fixed cores 88 and 89 respectively.Coils 86 and 87 are fixed to pposite ends of an arm 90 which, in turn,is fixed to a vane 91 for a nozzle 92.

A spring biased support for a vane inside a bellows 93 is shown in FIGS.8 and 9 including flexure springs 94 and 95 fixed to opposite ends of anarm 96 that is, in turn, fixed to the vane. Spring metal flexure strips94 and 95 are shown in FIG. -9.

A housing for a unit 20 is shown in FIG. including a piston 28 fixed toa piston rod 29. The structure shown in FIGURES 3 and 4 may be enclosedin a housing 97. The structure shown in FIG. 1 may be enclosed in ahousing portion 98 threaded to housing 97. Electric motor and auxiliaryconnections may be made in housing 99 integral with housing 98.

From the foregoing, it will be appreciated that the positive feedbackprovided by connections 36 and 37 shown in FIG. 1 will increase thespeed and improve response of piston 28 to changes in pressure inconnections 25 and 26. In other words, diaphragms 40 and 41 tend to movevane 34 in a direction to increase pressure as required by control 42.

What is claimed is:

1. A hydraulic positioning device comprising: a pump; a pressureresponsive device connected from the output of said pump; a bleed port.connected from the self same output of said pump; a hydraulic amplifieractuable in response to small changes in fluid pressure to restrictfluid flow through said portion varying degrees; a bleed nozzleconnected from said hydraulic amplifier; a vane movable to restrict thefluid flow through said bleed nozzle in varying degrees in a manner toactuate said hydraulic amplifier by increasing the pressure of fluidinside said nozzle; a control device responsive to an input signal tomove said vane, said control device being connected from said pressureresponsive device to said vane; return means to move said pressureresponsive device in a direction opposite that in which it is moved whenthe pressure of fluid inside said nozzle is increased; and meansresponsive to an increase in pressure inside said nozzle for applying adegree of force to move said vane toward said nozzle.

2. The invention as defined in claim 1, wherein said return meansincludes a second pump, said pressure responsive device is connectedfrom the output of said second pump, a second bleed port connected fromthe same output of said second pump, a second hydraulic amplifieractuable in response to small changes in fluid pressure to restrictfluid flow through said second port in varying degrees, second'bleednozzle connected from said second hydraulic amplifier, said vane beingmovable to restrict fluid flow through second bleed nozzle in varyingdegrees in a manner to actuate said second hydraulic amplifier byincreasing the pressure of fluid inside said second nozzle, and thirdmeans responsive to an increase in pressure inside said second nozzlefor applying a degree of force to move said vane toward said secondnozzle.

3. The invention as defined in claim 2, wherein said pressure responsivedevice includes opposite sides of a piston inside a cylinder, saidpiston having a rod connected therewith, and a spring connecting saidpiston rod to said vane.

4. The invention as defined in claim 1, wherein said control deviceincludes an arm, electromagnetic means at one end of said arm includinga coil, said arm thereby being movable in response to current insidesaid coil, a weight at the other and of said arm, and a spring connectedfrom said pressure responsive device to adjacent said other end of saidarm.

5. A hydraulic positioning device comprising: a pump; a pressureresponsive device connected from the output of said pump, said deviceincluding a piston rod; a bleed port connected from said same output ofsaid pump; hydraulic amplifier actuable in response to small changes influid pressure to restrict fluid flow through said port in varyingdegrees; a bleed nozzle connected from said hydraulic amplifier; a vanemovable to restrict the fluid flow through said bleed nozzle in varyingdegrees in a manner to actuate said hydraulic amplifier by increasingthe pressure of fluid inside said nozzle; a control device responsive toan input signal to move said vane, said control device including aspring connecting said rod to said vane, the axes of said rod and springbeing generally parallel; and return means to move said pressureresponsive device in a direction opposite that in which it is moved toopen said nozzle by said control device, said control device furtherincluding a first pivoted arm having said vane connected thereto,electromagnetic means associated with said first arm for shifting thearm in one direction, said spring biasing the arm in the oppositedirection, second and third adjacent arms pivotally mounted at oppositeends for movement in generally parallel planes, said spring beingconnected to said second arm, said third arm being operatively engagedwith said rod, and means interconnecting said second and third armswhereby the position of said rod is translated through said second andthird arms, said spring and said first arm to said vane.

6. The invention of claim 5 wherein said first arm is pivotally mountedintermediate its ends, said electromagnetic means including a coil onsaid arm adjacent to one end thereof, said spring being connected tosaid first arm adjacent to the other end thereof, said vane beingpositioned intermediate said ends, said second and third arms beingpositioned generally laterally with respect to said first arm and inoverlying relationship therewith, and said interconnecting meanscomprising a lateral projection on said third arm engaging a downwardlyfacing surface of said second arm.

7. The invention of claim 6 wherein said rod is generally verticallydisposed and has an upwardly facing bearing surface, the free end ofsaid third arm engaging said bearing surface whereby upward movement ofsaid rod upwardly pivots said third arm, thereby lifting said second armand tensioning said spring.

8. A hydraulic positioning device comprising: a pump; a pressureresponsive device connected from the output of said pump, said deviceincluding a piston rod; a bleed port connected from said same output ofsaid pump; hydraulic amplifier actuable in response to small changes influid pressure to restrict fluid flow through said port in varyingdegrees; a bleed nozzle connected from said hydraulic amplifier; a vanemovable to restrict the fluid flow through said bleed nozzle in varyingdegrees in a manner to actuate said hydraulic amplifier by increasingthe pressure of fluid inside said nozzle; a control device responsive toan input signal to move said vane, said control device including aspring connecting said rod to said vane, the axes of said rod and springbeing generally parallel; and return means to move said pressureresponsive device in a direction opposite that in which it is moved toopen said nozzle by said control device, said rod and spring beinggenerally vertically disposed, said control device including at leasttwo pivoted arms extending laterally with respect to each other and inoverlying relationship with respect to said rod with the end of said rodbearing against a downwardly facing surface of one of said arms, theother arm carrying said vane, said spring interconnecting said arms, andelectromagnetic means for altering the position of said other arm andthereby the location of said vane with respect to said nozzle.

References Cited UNITED STATES PATENTS 3,023,763 3/1962 Lanctot 9l3872,995,116 8/1961 Dobbins 91-359 3,316,815 5/1967 Chapin et al 91-3S9PAUL E. MASLOUSKY, Primary Examiner US. Cl. X.R. 9 l3 59, 387

